In 11 finals in Paris, Nadal has only lost six sets as he matched the all-time record of most singles titles won at the same Grand Slam event set by Margaret Court at the Australian Open during the 1960s and 70s.
Djokovic had also squandered three set points in the second set and failed to serve out the fourth in the ninth game after being 5-2 in front. That seemed to unsettle him and he played poor game that culiminated in a wild backhand going long to give him the lead.
Nadal has already established himself as one of the five greatest men's tennis players in history. Thiem withstood a barrage of break points to hold in a marathon sixth game, which he thought he had won at 40-30 when he left a wide ball, only for the umpire to overrule the line judge.
Cecchinato, who was suspended for an 18-month term in 2016 during a match-fixing investigation, says he will cherish the memories he made in the French capital after he lost to Thiem in straight sets 7-5 7-6 (12-10) 6-1.
Dominic Thiem was vying for his first Grand Slam title on Sunday. So there was mild concern when Nadal called for the trainer midway through a game, requiring treatment on what looked like cramp in his hand.
Two breaks later Nadal was in a familiar position, serving for the title, and when another Thiem forehand dropped long, his arms were raised in celebration, yet again. Perhaps that was because unlike the 1980 Final, which was played out in glorious sunshine, the 2008 Final ended nearly in the dark, because it lasted for so long (more than five hours), and even by the time of the fourth set tie-break the gloom was gathering. Against Dominic Thiem, he is top 10, and today all the people was for me.
Krejcikova and Siniakova, who are both 22, were playing in their fifth major tournament together.
They knocked out the top-seeded pair of Timea Babos and Kristina Mladenovic in the quarterfinals.
Nadal has been crowned the French Open champion an incredible 11 times, following successes in 2005, 2006, 2007, 2008, 2010, 2011, 2012, 2013, 2014 and 2017.
In his trophy-laden 17-year career, the World No 1 has won titles on all surfaces.
The Spaniard also won the title without losing a set, becoming the third man to do so in the Open era after Ilie Nastase and Borg.
The No. 7-seeded Thiem, a 24-year-old from Austria, is appearing in his first Grand Slam final. Nadal, Federer, Novak Djokovic and Andy Murray - the so-called Big Four - have dominated the men's game to such a degree that Thiem is only the second player now younger than 28 to have reached a major singles final. There is a slight chance of rain, but not until later in the afternoon after 5pm.